Methods of manufacturing glass articles using anisothermal temperature profiles

ABSTRACT

According to one embodiment, a method of manufacturing a glass article having a three-dimensional shape includes heating a glass article blank to a temperature above a setting temperature and coupling the glass article blank to an open-faced mold. The open-faced mold includes a molding region that has a three-dimensional shape that generally corresponds to the shape of the glass article and has an anisothermal temperature profile within the molding region. The method further includes maintaining an anisothermal temperature profile along the glass article blank and cooling the glass article blank while the glass article blank is coupled to the molding region of the open-faced mold to set the shape of the glass article.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority under 35 U.S.C. § 119 ofU.S. Provisional Application Ser. No. 61/866,162 filed on Aug. 15, 2013the content of which is relied upon and incorporated herein by referencein its entirety.

FIELD

The present specification generally relates to molds for shaping glassarticles and, more specifically, to one-sided molds for glass articleshaving a three-dimensional shape and methods of using the same to shapeglass articles.

BACKGROUND

Glass articles can be incorporated as cover glasses in various consumerproducts, including interactive displays on consumer devices such asmobile phones and tablets. As glass articles become more widely utilizedin various consumer devices, the geometric complexities of the glassarticles also increases as manufacturers push the design envelope interms of both aesthetics and function. For example, certain products mayrequire that the glass articles be formed into complex shapes, such ascurved sections that wrap around the edges of a device, thus requiringadditional forming operations to achieve the desired geometry. However,the design requirements of certain products may dictate narrowtolerances of deviations away from the target shape.

Accordingly, alternative molds and methods for forming glass articlesmay be desired.

SUMMARY

According to one embodiment, a method of manufacturing a glass articlehaving a three-dimensional shape includes heating a glass article blankto a temperature above a setting temperature and coupling the glassarticle blank to an open-faced mold. The open-faced mold includes amolding region that has a three-dimensional shape that generallycorresponds to the shape of the glass article and has an anisothermaltemperature profile within the molding region. The method furtherincludes maintaining an anisothermal temperature profile along the glassarticle blank and cooling the glass article blank while the glassarticle blank is coupled to the molding region of the open-faced mold toset the shape of the glass article.

In another embodiment, a molding apparatus for forming a glass articleincludes an open faced mold that includes a molding region. The moldingregion has a contact face that has a three-dimensional shape thatgenerally corresponds to a shape of the glass article. A plurality ofvent holes is positioned within the molding region of the open-facedmold and extends through the contact face. The vent holes are in fluidcommunication with a vacuum pump. At least one cooling passage ispositioned in the open-faced mold, and includes a portion that ispositioned proximate to the molding region and is fluidly isolated fromthe plurality of vent holes and the contact face of the open-faced mold.The cooling passage generates an anisothermal temperature profile acrossthe glass article.

In yet another embodiment, a method of manufacturing a glass-articlehaving a three-dimensional shape includes heating a glass article blankto a temperature above a setting temperature and coupling the glassarticle blank to an open-faced mold. The open-faced mold has athree-dimensional shape that differs from a target shape for the glassarticle. Additionally, the open-faced mold has an anisothermaltemperature profile within the molding region. The method furtherincludes maintaining an anisothermal temperature profile along the glassarticle blank and cooling the glass article blank to a temperature belowa viscous temperature while the glass article blank is coupled to themolding region of the open-faced mold to set the shape of the glassarticle, and releasing the glass article from the open-faced mold.

Additional features and advantages of various embodiments will be setforth in the detailed description which follows, and in part will bereadily apparent to those skilled in the art from that description orrecognized by practicing the embodiments described herein, including thedetailed description which follows, the claims, as well as the appendeddrawings.

It is to be understood that both the foregoing general description andthe following detailed description describe various embodiments and areintended to provide an overview or framework for understanding thenature and character of the claimed subject matter. The accompanyingdrawings are included to provide a further understanding of the variousembodiments, and are incorporated into and constitute a part of thisspecification. The drawings illustrate the various embodiments describedherein, and together with the description serve to explain theprinciples and operations of the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A schematically depicts a top perspective view of a glass articlehaving two bent sides according to one or more embodiment shown ordescribed herein;

FIG. 1B schematically depicts a top perspective view of a glass articlehaving four bent sides according to one or more embodiment shown ordescribed herein;

FIG. 1C schematically depicts a top cross-sectional view of the glassarticle of FIG. 1 shown along line A-A according to one or moreembodiment shown or described herein;

FIG. 2 schematically depicts relaxation of a glass relating to itstemperature and cooling rate according to one or more embodiment shownor described herein;

FIG. 3 schematically depicts a front perspective view of a mold and aglass article according to one or more embodiment shown or describedherein;

FIG. 4 schematically depicts modeling results of out-of-planedisplacement that results from an in-plane temperature gradientaccording to one or more embodiment shown or described herein;

FIG. 5 schematically depicts modeling results of out-of-planedisplacement that results from a through-thickness temperature gradientaccording to one or more embodiment shown or described herein; and

FIG. 6 schematically depicts a top cross-sectional view of a glassarticle having ion exchange surface layers according to one or moreembodiment shown or described herein.

DETAILED DESCRIPTION

Reference will now be made in detail to various embodiments, examples ofwhich are illustrated in the accompanying drawings. Whenever possible,the same reference numerals will be used throughout the drawings torefer to the same or like parts. FIG. 3 schematically depicts anembodiment of a mold for use in conjunction with the molding methodsdescribed herein. In one embodiment, the method for manufacturing aglass article having a three-dimensional shape may generally includeheating a glass article blank to a temperature above a settingtemperature and coupling the glass article blank to an open-faced mold.The open-faced mold includes a molding region that has athree-dimensional shape that generally corresponds to the shape of theglass article and has an anisothermal temperature profile within themolding region. The method further includes cooling the glass articleblank while the glass article blank is coupled to the molding region ofthe open-faced mold to set the shape of the glass article. Variousembodiments of methods for manufacturing glass articles having athree-dimensional shapes as well as molds for use therein will bedescribed in further detail herein with reference to the figures.

Referring now to FIGS. 1A-1C, glass articles manufactured according tothe present disclosure are shown. The glass articles may be incorporatedinto consumer products, such as smartphones or tablet computers. Varioustechniques can be utilized to form the glass article 100 such that theglass article has a three-dimensional shape. As used herein, the phrase“three-dimensional shape” means that the glass article generally has ashape that, at least in part, deviates from planar. For example andwithout limitation, the glass article 100 can have one of a number ofthree-dimensional shapes, such as a sled shape in which edges 102 a, 102b curve away from a central portion, as depicted in FIG. 1A, or a dishshape in which edges 104 a, 104 b, 104 c, 104 d curve away from acentral portion, as depicted in FIG. 1B. In various embodiments, theglass article 100 may also have a substantially flat area 106, shown inthe cross-sectional view of the glass article 100 schematically depictedin FIG. 1C. Utilizing the forming techniques described herein mayprovide a glass article which has a substantially flat area thatexhibits low deviation from a planar configuration, for example, by anamount of less than or equal to about 200 μm across the central portionof the glass article 100.

The strength and mechanical reliability of the glass article 100 is afunction of its surface defect or flaw size density distribution and thecumulative exposure of the material to stress over time. For example,the glass article 100 depicted in FIG. 1A or FIG. 1B may be subjected tovarious kinds of thermal and mechanical stresses during manufacturing,for example, caused by forming, molding, and polishing. In particular,the glass article 100 may exhibit a high stress field at positionsproximate a highly contoured portion of the molding region of a mold(e.g., at points near the bent edges 102 a and 102 b) and a low stressfield at positions proximate to less contoured portions of the moldingregion of a mold (e.g., at points near substantially flat area 106depicted in FIG. 1C). In some embodiments, the glass article 100 isfurther subjected to stresses during strengthening processes, forexample, in ion exchange processing.

In one example, the glass article 100 is subjected to stress resultingfrom in-plane and through-thickness thermal gradients in the glass. Suchthermal gradients can result from the different heating and coolingrates that a glass article blank 101 (depicted in FIG. 3) is subjectedto as the glass article blank 101 is formed into a glass article 100.For example, these thermal gradients may be imparted to the glassarticle blank 101 from the mold 300 (depicted in FIG. 3) which is usedto form the glass article 100, different heating and cooling rates ofthe center of the mold and the edge of the mold, different contactconditions between the glass article blank 101 and the mold 300, or thelike. These thermal gradients can induce internal stresses to the glassarticle 100 and/or cause undesired distortions or warpage of the glassarticle 100. However, the thermal gradients can be utilized to impartcontrolled distortions or warpage in the glass article 100. For example,in various embodiments, thermal gradients may cause the glass articleblank 101 to warp into a desired three-dimensional shape. When thesethermal gradients are introduced to the glass article blank 101 within aparticular range of temperatures, the glass article 100 may set with thewarp after the glass article 100 is allowed to cool. The warp therebymodifies the final three-dimensional shape of the glass article 100.Alternatively, the thermal gradients can be utilized to impartcontrolled distortions or warpage in the glass article in excess ofdesign tolerances in order to compensate for subsequent warp of theglass article 100 caused by downstream manufacturing processes.

FIG. 2 is a plot illustrating the relaxation of a glass composition as afunction of cooling rate in accordance with one or more embodimentsdescribed herein. In the plot, the x-axis represents the cooling rate(in degrees Celsius (C.) per second (s)), while the y-axis representsthe setting zone temperature (in degrees Celsius (C.)). It is to beunderstood that the values presented on the graph are illustrative innature, and may vary with the glass composition. The plot illustrates aviscous zone 202, a viscoelastic or setting zone 204, and an elasticzone 206. As shown in FIG. 2, the viscous zone 202 refers to a state inwhich greater than about 95% of stresses in the glass have relaxed. Theviscoelastic or setting zone 204 refers to a state in which from about90% of the compressive stresses to about 10% of the compressive stressesin the glass have relaxed. The elastic zone 206 refers to a state inwhich less than about 5% of the compressive stresses in the glass haverelaxed. In some embodiments, the boundaries between the recitedviscosity zones may vary depending on the particular embodiment. Forexample, the transition between the viscous to the viscoelastic zonesmay occur from about 90% to about 95% relaxation and the transitionbetween the viscoelastic and elastic zones may occur from about 5% toabout 10% relaxation.

When a glass article blank 101 is to be formed into a glass article, theglass article blank 101 is heated to a temperature at which the glassarticle blank 101 is no longer in the elastic zone 206. In variousembodiments, the glass article blank 101 is heated to a temperatureabove a setting temperature. For a given cooling rate, the settingtemperature is the temperature below which stresses can develop in theglass. The temperature to which the glass article blank 101 is heatedcan be selected depending on various factors. In some embodiments, whenthe glass article blank 101 is heated to the temperature above thesetting temperature, the glass article blank 101 enters the viscous zone202 or the viscoelastic zone 204. Once heated, the glass article blank101 is introduced to a mold 300 for shaping.

FIG. 3 illustrates one example of a mold 300 for forming a glass articlehaving a three-dimensional shape in accordance with one or moreembodiments described herein. As shown in FIG. 3, mold 300 includes anopen-faced, single-sided mold form 302. The mold form 302 can be made ofany suitable material, such as aluminum, nickel, cast iron, or bronze,and may be uncoated or coated with a corrosion-resistant coating or athermal barrier coating. The mold form 302 includes a molding region 304that has a contact face 306. Contact face 306 has a three-dimensionalshape that generally corresponds to the shape of a glass article to beformed. Although the three-dimensional shape of the contact face 306generally corresponds to the shape of the glass article, the shape ofthe contact face 306 can differ from the finished design shape of theglass article. As discussed hereinabove, the rate at which the glassarticle blank 101 is cooled can cause the glass article blank 101 towarp such that the glass article 100 has a shape that differs from, butgenerally corresponds to, the shape of the contact face 306 of themolding region 304. The amount by which the shape of the contact face306 differs from the shape of the glass article 100 can vary dependingon the particular requirements of the end-user application into whichthe glass article 100 is installed. In general, for end-userapplications in which that glass article 100 covers a display,high-dimensional accuracy within the flat area 106 may be desired, whiledimensional variation at positions outside of the flat area 106 may beacceptable.

A plurality of vent holes 308 are positioned within the molding region304 of the open-faced mold form 302, and extend through the contact face306. The vent holes 308 are in fluid communication with a vacuum pump310. The vent holes 308 enable the glass article blank 101 to bemaintained in intimate contact with the mold 300 by a pressure imbalanceacross the glass article blank 101 without contacting a face of theglass article blank 101 opposite the mold form 302. Reducing oreliminating contact with the glass article blank 101 can reduce defectspresent in the final glass article 100.

In various embodiments, the mold 300 is heated to an elevatedtemperature before the glass article blank 101 is coupled. In someembodiments, the mold 300 is heated to a temperature above ambienttemperature that is below the setting temperature of the glass. The mold300 can be heated using any of a variety of conventional techniques. Forexample, heating elements may be placed at the ceiling of the furnace,located above the mold and in close proximity to the edges of the mold,or embedded in the mold. Such heating elements may be made of siliconcarbide, tungsten, nichrome, or the like. In some instances, an emitterplate may be used in conjunction with ceiling-mounted heating elementsto provide more uniform heating. The heated glass article blank 101 isintroduced into molding region 304 of the mold 300 and the vacuum pumpdraws fluid through the vent holes 308 to bring the heated glass articleblank 101 into contact with the heated contact face 306. The glassarticle blank 101 is held in position on the mold form 302 by at least apartial vacuum created by the vacuum pump 310 along the contact face306.

The mold 300 may further include at least one cooling passage 312,illustrated in FIG. 3 by dashed lines. In various embodiments, thecooling passage 312 can provide a fluid cooling stream to the mold form302 at positions adjacent to the molding region 304. The cooling passage312 may be positioned in the mold 300 in a serpentine pattern (as shownin FIG. 3), a swirl pattern, or another pattern that generates a desiredtemperature profile across the contact face 306. In some embodiments,the fluid cooling stream incorporates a gas that is inert to the mold300 in the temperature range in which the mold 300 operates, for exampleair, nitrogen, helium, neon, or the like, although other fluid coolingstreams, and other cooling mechanisms, can be employed. In the depictedembodiment, the cooling passage 312 includes a portion that ispositioned proximate to the molding region 304 and is fluidly isolatedfrom the vent holes 308 and the contact face 306 of the mold 300.Accordingly, when the fluid cooling stream is introduced into thecooling passage 312, the cooling passage 312 cools a portion of the mold300 proximate to the molding region 304 with the fluid cooling stream.The cooling passage 312 generates a non-uniform, anisothermaltemperature profile across the contact face 306. Restated, the coolingpassage 312 can be used to control the temperature of portions of themold 300 such that a first portion of the mold 300 has a firsttemperature and a second portion of the mold 300 has a secondtemperature different from the first temperature. As such, the mold 300exhibits an anisothermal temperature profile within the molding region304. In some embodiments, a fluid heating stream, rather than a fluidcooling stream, can be introduced through one or more of the coolingpassages 312 to generate a thermal gradient across the thickness of theglass article 100.

The flow rate of the fluid cooling stream through the cooling passage312 can be modified to generate one of a plurality of anisothermaltemperature profiles within the flat area 106. In some embodiments, thetemperature of the contact face 306 at positions proximate to the edgesof the molding region 304 (i.e., regions A and C depicted in FIG. 3) isgreater than the temperature of the contact face 306 at positions distalfrom the edges of the molding region 304 (i.e., region B in FIG. 3). Inother embodiments, the temperature of the contact face 306 at positionsproximate to the edges of the molding region 304 is less than thetemperature of the contact face 306 at positions distal from the edgesof the molding region 304. While FIG. 3 illustrates three verticalregions (A, B, and C) representing various regions of contact face 306having different temperatures from one another, it is to be understoodthat the regions may correspond to different shapes, sizes, andorientations.

In general, the mold 300 and glass article blank 101 are both heated todesired initial temperatures above the ambient temperature in which themold 300 is positioned. The glass article blank 101 is heated to atemperature greater than the elastic temperature range for the glasscomposition. The glass article blank 101 is brought into contact withthe contact face 306 of the mold 300. With the glass article blank 101in contact with the contact face of the mold 300, the vacuum pump 310draws fluid through the vent holes 308, reducing the pressure along theside of the glass article blank 101 positioned proximate to the contactface 306. The vacuum pump 310 maintains a pressure imbalance across theglass article blank 101, thereby clamping the glass article blank 101 tothe contact face 306 of the mold 300. The pressure imbalance caused bythe vacuum pump 310 may overcome the strength of the glass article blank101 at the elevated temperature so that the glass article blank 101 willconform to the shape of the contact face 306 of the mold 300.

The temperature of the glass article blank 101 and the mold 300 arereduced from the initial temperatures. As the temperature of the glassarticle blank 101 decreases, the glass article blank 101 will continueto conform to the shape of the contact face 306. As the fluid coolingstream is directed through the cooling passages 312, the fluid coolingstream draws heat away from the contact face 306 by conduction and/orconvection, the mold 300 acts as a heat sink to the glass article blank101, drawing heat away from the glass article blank 101. As thetemperature of the glass article blank 101 is reduced, the strength ofthe glass article blank 101 increases. Additionally, as the temperatureof the glass article blank 101 and the mold 300 decrease, the glassarticle blank 101 and the mold 300 will reduce in size due to therespective coefficients of thermal expansion. However, because the glassarticle blank 101 and the mold 300 likely have different coefficients ofthermal expansion, the relative change in size of the glass articleblank 101 and the mold 300 due to the variations in thermal expansionmay induce stress into the glass article blank 101. Because the glassarticle blank 101 is simultaneously dropping, in temperature, stressesinduced to the glass article blank 101 as the glass article blank 101 isbeing cooled may be maintained in the glass article 100 at a temperaturein the elastic temperature range.

Additionally, because an anisothermal temperature gradient is maintainedon the glass article blank 101 in the through-thickness direction and/orthe in-plane direction of the glass article blank 101, portions of theglass article blank 101 at higher temperatures may tend to expandrelative to portions of the glass article blank 101 at lowertemperatures. The variation in expansion between portions of the glassarticle blank 101 may introduce stress into the glass article blank 101as the glass article blank 101 reduces in temperature through theviscoelastic temperature range towards the elastic temperature range.The profile of the glass article blank 101, therefore, may change whencomparing the profile at which the two- or three-dimensional shape isset into the glass article blank 101 to the profile of the glass article100 at room temperature. In particular, the portions of the glassarticle blank 101 that are maintained at elevated temperatures may tendto contract more than the portions of the glass article blank 101 thatare maintained at comparatively lower temperatures. The contraction ofcertain portions of the glass article 100 may tend to warp the glassarticle 100 away from the shape of the contact face 306 of the mold 300.

Because the rate at which heat is drawn away from the glass articleblank 101 corresponds to the rate at which the cooling passages 312 drawheat away from the contact face 306, the anisothermal temperatureprofile of the contact face 306 of the mold 300 can cause a similaranisothermal temperature profile, or thermal gradient, to be generatedacross the glass article blank 101. The anisothermal temperature profileis generated across the glass article blank 101 as FIGS. 4 and 5illustrate displacement in the glass article blank 101 resulting fromthermal gradients generated across the glass article blank 101 due tothe cooling passages 312 in the mold 300.

FIG. 4 depicts displacement resulting from a thermal gradient across anin-plane direction of the glass article blank 101. In FIG. 4, thetemperature of the glass article blank 101 at a point 402 at a positionproximate the edges of the glass article blank 101 is greater than atemperature of the glass article blank 101 at a point 404 at a positiondistal from the edges of the glass article blank. Thus, points proximatethe edge of the glass article blank 101 (e.g., points within region 406)exhibit greater cumulative displacement than points distal (e.g., pointswithin region 408) from the edges of the glass article blank 101, andthe points within the region 406 have greater displacement than thepoints within the region 408. In various embodiments, the displacementwithin regions 410, 412, and 414 falls within the displacement in theregion 406 and the region 408. Accordingly, when the contact face 306 ofthe mold 300 generates such a thermal gradient across the glass articleblank 101, the edges of the glass article blank 101 will tend to deflectfrom the contact face 306 of the mold 300. Similarly, if the temperatureof the glass article blank 101 at a point positioned proximate to theedges of the glass article blank 101 is less than a temperature of theglass article blank 101 at a point positioned distal from the edges ofthe glass article blank 101, the edges of the glass article blank 101will tend to deflect toward the contact face 306 of the mold 300. Invarious embodiments, the anisothermal temperature profile, and thethermal gradient caused by the anisothermal temperature profile may becontrolled by adjusting the flow rate of the fluid cooling streamthrough the cooling passage 312. Adjusting the flow rate of the fluidcooling stream, therefore, may provide some control over the shape ofthe glass article 100 in addition to that provided by the contours ofthe mold 300.

FIG. 5 illustrates displacement resulting from a thermal gradientthrough a thickness of the glass article blank 101. In FIG. 5, thetemperature of a face of the glass article blank 101 proximate thecontact face 306 is less than a temperature of a face of the glassarticle blank 101 at a distal position from the contact face 306. Thus,the face of the glass article blank 101 proximate the contact face 306exhibits less thermal expansion than the face of the glass article blank101 at a distal position from the contact face 306. Accordingly, theglass article blank 101 tends to warp into a bow-like shape (e.g.,positive displacement within a region 416 relative to a region 418 wherethe positive direction is away from the mold). Similarly, if thetemperature of a face of the glass article blank 101 proximate thecontact face 306 is greater than a temperature of a face of the glassarticle blank 101 distal from the contact face 306, the glass articleblank 101 tends to warp into a dome shape.

In some embodiments, a heating element (not shown) is positioned in themold 300 opposite from and spaced apart from the contact face 306. Theheating element, along with the cooling passage 312 of the mold 300 cangenerate a thermal gradient through the thickness of the glass article100. Restated, the face of the glass article 100 in contact with thecontact face 306 can have a temperature different from a temperature ofthe face of the glass article 100 spaced apart from the contact face306. However, it should be understood that inclusion of a heatingelement is optional and that a heating element need not be employed togenerate a thermal gradient through the thickness of the glass article100.

In various embodiments, the flow rate of the fluid cooling stream can beadjusted to alter the thermal gradient across an in-plane direction ofthe glass article blank 101 and/or through a thickness of the glassarticle blank 101. By altering the thermal gradient in the glass articleblank 101, the glass article blank 101 can be formed such that thethree-dimensional shape of the glass article 100 generally correspondsto a desired design shape for the glass article 100. In particular, thethermal gradient can be controlled to cause a pre-determined warp of theglass article blank 101 that contributes to the three-dimensional shapeof the glass article 100. Methods for manufacturing a glass article 100with a three-dimensional shape using the mold 300 will now be describedin more detail.

According to an exemplary method, a glass article blank 101 is heated toa temperature above a setting temperature. In various embodiments, theglass article blank 101 is heated to a temperature such that the glassarticle blank 101 is in a viscous state. In some embodiments, the glassarticle blank 101 is heated to a temperature at which greater than about75% of the stresses of the glass article blank 101 are relaxed for agiven cooling rate. Other temperatures may be utilized depending on therequirements of the glass composition and/or glass article 100. Forexample, the glass article blank 101 may be heated to a temperature atwhich greater than about 80% of the stresses of the glass are relaxedfor a given cooling rate, for example greater than about 85% of thestresses of the glass are relaxed for a given cooling rate, for examplegreater than about 90% of the stresses of the glass are relaxed for agiven cooling rate, for example greater than about 95% of the stressesof the glass are relaxed for a given cooling rate.

In various embodiments, the mold 300 is preheated to an elevatedtemperature above ambient temperature. The mold 300 can be heated to atemperature less than the temperature to which the glass article blank101 is heated. For example, the mold 300 can be heated to a temperatureat which the glass article blank 101 would be in a viscoelastic state.In various embodiments, after the mold is preheated, the fluid coolingstream is passed through the cooling passages 312 of the mold 300 tofurther control the temperature of the mold 300. In particular, thefluid cooling stream is passed through the cooling passages 312 tocontrol a first portion of the mold 300 to have a first temperature anda second portion of the mold 300 to have a second temperature such thatwhen the glass article blank 101 is coupled to the mold 300, the mold300 may have an anisothermal temperature profile within the moldingregion 304.

Next, the glass article blank 101 is coupled to the mold 300 such thatthe glass article blank 101 is brought into at least partial contactwith the contact face 306 of the molding region 304. The glass articleblank 101 is then conformed to the contact face 306 by enabling thevacuum pump 310, which draws fluid through the vent holes 308, therebybringing the glass article blank 101 into contact with the contact face306 and holding the glass article blank 101 in position on the contactface 306.

The glass article blank 101 is cooled while the glass article blank 101is coupled to the molding region 304 of the mold 300 to set the shape ofthe glass article 100 into the glass article blank 101. For example, themold 300 can act as a heat sink, drawing the heat away from the glassarticle blank 101. As described above, the flow rate of the fluidcooling stream can be controlled to adjust the cooling rate of thecontact face 306 and glass article blank 101. While the glass articleblank 101 is cooled from the elevated temperature and remains in contactwith the contact face 306, a thermal gradient may be maintained througha thickness and/or across an in-plane direction of the glass articleblank 101. The thermal gradient may be caused by different cooling ratesat different locations along the surfaces of the glass article blank101. In one embodiment, the heat conducted away from the face of theglass article blank 101 that contacts the mold 300 may be greater thanthe heat conducted and/or convected away from the side opposite the mold300, thereby maintaining a thermal gradient through the thickness of theglass article blank 101. In some embodiments, while one side of theglass article blank 101 (e.g., the face of the glass article blank 101proximate the contact face 306) is cooled, a side of the glass articleblank 101 opposite the side that contacts the mold 300 can be heatedusing a heating element to generate or modify a thermal gradient throughthe thickness of the glass article blank 101.

After cooling, the glass article 100 is decoupled from the mold 300. Invarious embodiments, the glass article 100 is decoupled from the mold300 when a maximum temperature of the glass article 100 is within aviscoelastic temperature range of the glass article 100 for a givencooling rate. However, in some embodiments, the glass article 100 isdecoupled from the mold 300 when a maximum temperature of the glassarticle is within an elastic temperature range of the glass article 100for a given cooling rate. For example, the glass article 100 can bedecoupled from the mold 300 at a temperature at which less than about 5%of the stresses of the glass are relaxed for a given cooling rate, forexample a temperature at which less than about 10% of the stresses ofthe glass are relaxed for a given cooling rate, for example atemperature at which less than about 15% of the stresses of the glassare relaxed for a given cooling rate, for example a temperature at whichless than about 20% of the stresses of the glass are relaxed for a givencooling rate.

Optionally, in various embodiments, surface strengthening, for exampleby an ion exchange process, is performed on the glass article 100 afterthe glass article is decoupled from the mold. In one embodiment depictedin FIG. 6, the ion exchange process introduces compressive layers intothe surfaces of the glass article 100 by exchanging ions in the glass.These compressive layers, referred to herein as ion exchange surfacelayers 110, in the surfaces of the glass article 100 have a depth oflayer 108 that extends from the surface layers. Regions of the glassarticle 100 in which the chemically strengthening process does notintroduce compressive layers may exhibit tension to compensate for theincrease in compression in the ion exchange surface layers 110. Theforming of the ion exchanged surface layers 110 may modify the shape ofthe glass article 100 so that the glass article 100 has a shape thatdiffers from the shape of the molding region of the open-faced mold.First, chemically strengthening typically occurs at elevatedtemperatures, which may anneal the glass article 100, thereby reducingthe internal stress introduced in a forming process, as describedherein. Reducing the internal stresses may reduce the induced deflectionof the glass article 100. Second, chemically strengthening the glassarticle 100 may result in the expansion of the glass article 100 aslarger potassium ions replace smaller sodium ions. For asymmetricalshapes, a stable shape (i.e., the shape having a minimum energy) is awarped shape. Thus, in embodiments in which a chemical strengtheningprocess is performed, the shape of the molding region of the mold 300can differ from a target shape for the glass article 100 by apredetermined amount such that the shape of the glass article 100 afterthe chemically strengthening process generally corresponds to the targetshape for the glass article 100 within acceptable tolerances. The shapeof the molding region of the mold 300 can compensate for warp caused bysubsequent chemical strengthening processes to yield a glass article 100with a shape that corresponds to the target shape for the glass article100.

In various embodiments, the cooling rate can be adjusted, for example,to finely tune the temperature gradient across the glass article blank101. The methods described herein can be used, for example, as aniterative inspection parameter regime on a glass article manufacturingprocess. After the glass article blank 101 is cooled, and the glassarticle 100 is decoupled from the mold 300, the three-dimensional shapeof the glass article 100 is compared to a target shape for the glassarticle 100. For example, the three-dimensional shape of the glassarticle 100 can be compared to a computer-aided design (CAD) model forthe glass article 100 using conventional inspection techniques. If theshape of the glass article 100 is within acceptable tolerances, asubsequent glass article blank 101 is heated for forming. Acceptabletolerances can vary depending on the particular embodiment. For example,in various embodiments, an acceptable tolerance for the shape of theglass article 100 is within approximately 100 μm of the nominaldimensions of the CAD model, although other tolerances can beacceptable.

If the three-dimensional shape of the glass article 100 differs from thetarget shape by an amount outside acceptable tolerances, the flow rateis adjusted to a flow rate that generates an alternate anisothermaltemperature profile for the mold 300. When glass is processed accordingto the method, a subsequent glass article blank 101 is heated. Thesubsequent glass article blank 101 is coupled to the mold 300, cooled atthe second flow rate, decoupled from the mold 300, and the shape of thesubsequent glass article is compared to the target shape. The method canbe repeated with alternate anisothermal temperature profiles until theshape of the glass article is within the acceptable tolerances.

It should now be understood that methods of manufacturing glass articlesaccording to the present disclosure may be used to produce glassarticles having three-dimensional shapes. Glass article blanks areheated to a temperature above the setting temperature of the glass andare introduced to an open-faced mold having a shape that generallycorresponds to the shape of the desired glass article. An anisothermaltemperature profile is maintained along the glass article blank by theopen-faced mold. The glass article blank is cooled while contact betweenthe glass article blank and the open-faced mold is maintained. Theanisothermal temperature profile of the open-faced mold may induce warpinto the glass article such that the shape of the glass article differsfrom the shape of the open-faced mold. Various embodiment of the methodsand apparatuses described herein enable glass articles to bemanufactured to compensate for warp that can occur in down-streamprocesses. By compensating for down-stream processing warp during glassarticle shaping, the methods and apparatuses described herein may resultin fewer non-conforming glass articles and increased manufacturingefficiencies.

In a first aspect, the disclosure provides a method of manufacturing aglass article having a three-dimensional shape includes heating a glassarticle blank to a temperature above a setting temperature; controllinga first portion of a molding region of an open-faced mold to have afirst temperature and a second portion of the molding region of theopen-faced mold to have a second temperature effective to generate ananisothermal temperature profile within the molding region, the moldingregion having a three-dimensional shape that generally corresponds tothe shape of the glass article; coupling the glass article blank to theopen-faced mold; and cooling the glass article blank while coupled tothe molding region of the open-faced mold to set the shape of the glassarticle.

In a second aspect, the disclosure provides a method of manufacturing aglass article having a three-dimensional shape may include heating aglass article blank to a temperature above a setting temperature;controlling a first portion of an open-faced mold to have a firsttemperature and a second portion of the open-face mold to have a secondtemperature effective to generate an anisothermal temperature profilefor the open-faced mold, the open-faced mold having a three-dimensionalshape that differs from a target shape for the glass article; couplingthe glass article blank to the open-faced mold; cooling the glassarticle blank to a temperature below a viscous temperature while coupledto the open-faced mold to set the shape of the glass article; andreleasing the glass article from the open-faced mold.

In a third aspect, the disclosure provides the method of the first orsecond aspects may include cooling a portion of the open-faced moldproximate to the molding region with a fluid cooling stream.

In a fourth aspect, the disclosure provides the methods of the firstthrough third aspects, wherein when the glass article blank is beingcooled, a thermal gradient is maintained through a thickness of theglass article blank.

In a fifth aspect, the disclosure provides the methods of the firstthrough fourth aspects, wherein when the glass article blank is beingcooled, a thermal gradient is maintained across an in-plane direction ofthe glass article blank.

In a sixth aspect, the disclosure provides the methods of any of thefirst through fifth aspects further includes decoupling the glassarticle from the open-faced mold when a maximum temperature of the glassarticle is within a viscoelastic temperature range of the glass articlefor a given cooling rate.

In a seventh aspect, the disclosure provides the methods of any of thefirst through fifth aspects further includes decoupling the glassarticle from the open-faced mold when a maximum temperature of the glassarticle is within an elastic temperature range of the glass article fora given cooling rate.

In an eighth aspect, the disclosure provides the methods of any of thefirst through seventh aspects further includes heating the glass articleblank along a side opposite a side of the glass article blank thatcontacts the open-faced mold.

In a ninth aspect, the disclosure provides the methods of any of thefirst through eighth aspects, wherein a shape of the glass articlediffers from the shape of the molding region of the open-faced mold.

In a tenth aspect, the disclosure provides the methods of any of thefirst through ninth aspects further includes forming an ion exchangedsurface layer having a depth of layer into the glass article.

In an eleventh aspect, the disclosure provides the methods any of thefirst through tenth aspects, wherein forming the ion exchanged surfacelayer modifies the shape of the glass article so that the glass articlehas a shape that differs from the shape of the molding region of theopen-faced mold.

In a twelfth aspect, the disclosure provides the methods of any of thefirst through eleventh aspects, wherein the molding region comprises ahigh contoured portion and a low contoured portion, and the glassarticle comprises a high stress field at positions proximate to the highcontoured portion of the molding region and a low stress field atpositions proximate to the low contoured portion of the molding region.

In a thirteenth aspect, the disclosure provides the method of any of thefirst through twelfth aspects, wherein cooling the glass article blankis performed at a first flow rate. The method may further includedetermining that the three-dimensional shape of the glass articlediffers from the target shape for the glass article; selecting a secondflow rate, the second cooling rate differing from the first coolingrate, wherein the second flow rate generates an alternate anisothermaltemperature profile for the open-faced mold; and cooling a subsequentglass article blank according to the second flow rate to the settingtemperature while coupled to the open-faced mold to set athree-dimensional shape of a subsequent glass article.

In a fourteenth aspect, the disclosure provides the methods of any ofthe first through thirteenth aspects, wherein the three-dimensionalshape of the glass article generally corresponds to the target shape forthe glass article.

In a fifteenth aspect, the disclosure provides the methods of any of thefirst through fourteenth aspects, wherein heating the glass articleblank to the temperature above the setting temperature comprises heatingthe glass article blank to a temperature at which greater than about 75%of the stresses of the glass article blank are relaxed for a givencooling rate.

In a sixteenth aspect, the disclosure provides the methods of any of thefirst through fifteenth aspects, wherein cooling the glass article blankto the setting temperature while coupled to the open-faced moldcomprises cooling the glass article blank to a temperature at which lessthan approximately 20% of the stresses of the glass are relaxed for agiven cooling rate.

In a seventeenth aspect, the disclosure provides a molding apparatus forforming a glass article that includes an open-faced mold comprising amolding region having a contact face that has a three-dimensional shapethat generally corresponds to a shape of the glass article; a pluralityof vent holes positioned within the molding region of the open-facedmold and extending through the contact face, the vent holes in fluidcommunication with a vacuum pump; and at least one cooling passagepositioned in the open-faced mold, the at least one cooling passageincludes a portion that is positioned proximate to the molding regionand is fluidly isolated from the plurality of vent holes and the contactface of the open-faced mold, wherein the at least one cooling passagegenerates an anisothermal temperature profile across the glass article.

In an eighteenth aspect, the disclosure provides the molding apparatusof the seventeenth aspect further including a heating element positionedopposite from and spaced apart from the contact face.

In a nineteenth aspect, the disclosure provides the molding apparatusesof the seventeenth or eighteenth aspects, wherein a temperature of thecontact face of the open-faced mold at a position proximate to edges ofthe molding region is greater than a temperature of the contact face atpositions distal from the edges.

In a twentieth aspect, the disclosure provides the molding apparatus ofany of the seventeenth through nineteenth aspects, wherein a temperatureof the contact face of the open-faced mold at a position proximate toedges of the molding region is less than a temperature of the contactface at positions distal from the edges.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the embodiments describedherein without departing from the spirit and scope of the claimedsubject matter. Thus it is intended that the specification cover themodifications and variations of the various embodiments described hereinprovided such modification and variations come within the scope of theappended claims and their equivalents.

The invention claimed is:
 1. A method of manufacturing a glass articlehaving a three-dimensional shape comprising: heating a glass articleblank to a temperature above a setting temperature; controlling a firstportion of a molding region of an open-faced mold to have a firsttemperature and a second portion of the molding region of the open-facedmold to have a second temperature effective to generate an anisothermaltemperature profile within the molding region, the molding region havinga three-dimensional shape that generally corresponds to thethree-dimensional shape of the glass article, wherein the first andsecond temperatures are above an ambient temperature and below thesetting temperature; coupling the heated glass article blank to acontact face of the open-faced mold including the anisothermaltemperature profile; maintaining an anisothermal temperature profilealong the glass article blank; cooling a portion of the open-faced moldproximate to the molding region by directing a fluid cooling streamthrough a cooling passage in the open-faced mold, wherein the coolingpassage comprises a portion that is positioned proximate to the moldingregion and is fluidly isolated from the contact face of the open-facedmold; adjusting a flow rate of the fluid cooling stream through thecooling passage to control the anisothermal temperature profile alongthe glass article blank; and cooling the glass article blank whilecoupled to the molding region of the open-faced mold to set thethree-dimensional shape of the glass article, wherein when the glassarticle blank is being cooled, a thermal gradient is maintained througha thickness of the glass article blank thereby causing a pre-determinedwarp of the glass article blank that contributes to thethree-dimensional shape of the glass article.
 2. The method of claim 1,further comprising decoupling the glass article from the open-faced moldwhen a maximum temperature of the glass article is within a viscoelastictemperature range of the glass article for a given cooling rate.
 3. Themethod of claim 1, further comprising heating the glass article blankalong a side opposite a side of the glass article blank that contactsthe open-faced mold.
 4. The method of claim 1, wherein a shape of theglass article differs from the shape of the molding region of theopen-faced mold.
 5. The method of claim 1, further comprising forming anion exchanged surface layer having a depth of layer into the glassarticle.
 6. The method of claim 5, wherein forming the ion exchangedsurface layer modifies the shape of the glass article so that the glassarticle has a shape that differs from the shape of the molding region ofthe open-faced mold.
 7. The method of claim 1, wherein the moldingregion comprises a high contoured portion and a low contoured portion,and the glass article comprises a high stress field at positionsproximate to the high contoured portion of the molding region and a lowstress field at positions proximate to the low contoured portion of themolding region.
 8. A method of manufacturing a glass article having athree-dimensional shape comprising: heating a glass article blank to atemperature above a setting temperature; controlling a first portion ofan open-faced mold to have a first temperature and a second portion ofthe open-face mold to have a second temperature effective to generate ananisothermal temperature profile for the open-faced mold, the open-facedmold having a three-dimensional shape that differs from a target shapefor the glass article, wherein the first and second temperatures areabove an ambient temperature and below the setting temperature; couplingthe heated glass article blank to a contact face of the open-faced moldhaving the anisothermal temperature profile; maintaining an anisothermaltemperature profile along the glass article blank; cooling a portion ofthe open-faced mold proximate to the molding region by directing a fluidcooling stream through a cooling passage in the open-faced mold, whereinthe cooling passage comprises a portion that is positioned proximate tothe molding region and is fluidly isolated from the contact face of theopen-faced mold; adjusting a flow rate of the fluid cooling streamthrough the cooling passages to control the anisothermal temperatureprofile along the glass article blank; cooling the glass article blankto a temperature below a viscous temperature while coupled to theopen-faced mold to set the three-dimensional shape of the glass article,wherein when the glass article blank is being cooled, a thermal gradientis maintained through a thickness of the glass article blank therebycausing a pre-determined warp of the glass article blank thatcontributes to the target shape of the glass article; and releasing theglass article from the open-faced mold.
 9. The method of claim 8,wherein cooling the glass article blank is performed at a first flowrate, the method further comprising: determining that thethree-dimensional shape of the glass article differs from the targetshape for the glass article; and selecting a second flow rate, thesecond cooling rate differing from the first cooling rate, wherein thesecond flow rate generates an alternate anisothermal temperature profilefor the open-faced mold; and cooling a subsequent glass article blankaccording to the second flow rate to the setting temperature whilecoupled to the open-faced mold to set a three-dimensional shape of asubsequent glass article.
 10. The method of claim 8, wherein thethree-dimensional shape of the glass article generally corresponds tothe target shape for the glass article.
 11. The method of claim 8,wherein heating the glass article blank to the temperature above thesetting temperature comprises heating the glass article blank to atemperature at which greater than about 75% of the stresses of the glassarticle blank are relaxed for a given cooling rate.
 12. The method ofclaim 8, wherein cooling the glass article blank to the settingtemperature while coupled to the open-faced mold comprises cooling theglass article blank to a temperature at which less than approximately20% of the stresses of the glass are relaxed for a given cooling rate.